The field of the invention is that of internal combustion engines of the fuel injector type, and the invention relates more particularly to fuel injection engines having heating devices for heating fuel as it is furnished to engine cylinders.
It has been proposed that self-regulating electrical resistance heaters be arranged in air-fuel inlet channels in the cylinder head of an internal combustion engine of the fuel injector type to intercept fuel sprayed into the inlet channels by the fuel injectors. In that way the heaters heat the fuel just as it is furnished to the engine cylinders to enhance fuel vaporization and to reduce engine pollution emissions, particularly during the engine warm-up period. The heaters require a substantial amount of electrical power from the engine power supply and it would be desirable to deenergize the heaters after engine warm-up occurs. However, it is found that deenergizing of the heaters results in formation of cold spots at the heater locations which frequently interfere with full vaporizing of the fuel during normal running operation of the engine thereafter.